1. Field of the Invention
The invention is directed to a method for spatial allocation of information referring to a location and is directed to a terminal unit for carrying out the method.
2. Discussion of the Prior Art
For automatic evaluation of location-oriented information, for example, traffic information, determination of the location to which the information refers and a match with the location at which the terminal unit is located is required in the terminal unit receiving this information. A problem in this respect is that the geographic positions of locations are generally determined neither precisely, nor definitively because, for example, locations such as street intersections, forks or branch-offs, etc. are assigned different positions on different maps, and when updating maps, etc. the geographic positions of locations in the map sometimes change or new locations such as new branch-offs are added.
A possible method for spatial allocation in a terminal unit of information referring to a location would be to issue a standardized identification number to important locations such as stretches of road, highway exits, etc., wherein the information provider and the terminal unit both have identical tables of identification numbers and associated locations. While this method is definitive, it cannot be updated continuously without elaborate centralized administrative management. Further, because of the abstract issuing of identity numbers, in the case of an old table of codes in the terminal unit, a spatial allocation of information received by an information provider is not possible at least in the case of a new location, such as a new highway exit, designated by a new identity number.
In another conceivable method, names can be assigned to the locations. In this case, long roads, especially highways, must be divided up through additions such as "between junction x and y". With respect to an automatic evaluation of information sent from an information provider to a terminal unit, problems can arise due to different types of writing, for example, umlauts and abbreviations, as well as different designations, for example, Stachus and Karlsplatz in Munich, and the nonstandardized naming of exits, etc. by the locality adjoining the exit.
Further, allocation of a location through geographic coordinates such as the geographic longitude and latitude of a location is also possible. However, the problem in this case is that the same location, for example, a street intersection, is located in different positions on different maps, which causes problems when the traffic information center receives data referring to different maps or when the geographic coordinates of a location in the map change due to an update of the map. Even in the case of relatively minor inaccuracies in the indication of geographic coordinates on a map, this location can no longer be definitively allocated in a terminal unit. However, a definitive allocation of locations to standardized geographic coordinates would entail highly complicated administration for definition and upkeep.